Decoder device and receiver using the same

ABSTRACT

An object of the present application is to provide the display of motion picture data used in both of analog and digital broadcasts with high picture quality and a common user interface. The above object can be achieved by providing a plurality of picture format converters, a plurality of OSD circuits, and means for storing motion picture data used in an analog broadcast in a common memory.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of application Ser. No. 09/241,614 filedon Feb. 2, 1999, now U.S. Pat. No. 6,310,654, the contents of which arehereby incorporated herein by reference in their entirety.

This application is related to application Ser. No. 09/984,509 filed onOct. 30, 2001, now U.S. Pat. No. 6,452,638, which, like the presentapplication, is a division of application Ser. No. 09/241,614 filed onFeb. 2, 1999, now U.S. Pat. No. 6,310,654.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a digital data transmitting/receivingsystem for transmitting motion image or picture data coded by theInternational Standard of ISO/IEC, MPEG-2 or the like for coding motionpicture data with high efficiency. The present invention also relates toa digital data decoder device for decoding coded motion picture data andoutputting it therefrom and a receiver for receiving displayed digitaldata. Incidentally, a description will be made below of an example inwhich the present invention is applied to a digital broadcast. However,the present invention is not necessarily limited to this. The presentinvention can be also applied to an example related to the transmissionand reception of data such as data communications or the like in asimilar mechanism.

2. Description of the Related Art

Due to an increase in the amount of digital motion image or picturedata, high-efficiency coding means performs compression thereon toeliminate redundancy or the like and thereafter transmits or records thecoded motion picture data, whereby the cost of transmission or recordingcan be reduced. As the high-efficiency coding means, there is well knownan MPEG-2 system standardized by ISO/IEC/JTC1/SC29/WG11.

As to the coding based on the MPEG-2 system, respective frames of motionpicture data are separated into an I frame (Intra Picture) coded withouthaving a frame (reference frame) referred as a predicted value, a Pframe (Predictive Picture) with only frames lying in the forwarddirection in display order as reference frames, and a B frame(Bidirectional Picture) with each frame lying in the forward directionand each frame lying in the backward direction as reference frames. Uponactual coding, two reference frames lying in the forward and backwarddirections are required to exist upon decoding the B frame, and the datacoding is performed after the sequence of frames is skillfullyinterchanged.

While a decoder device successively decodes coded motion picture datatransmitted in coding order, it is necessary to temporarily store thedecoded data in a memory and re-arrange or sort the same in accordancewith display order. It is also necessary to use decoded data of the Iand P frames as reference data upon the subsequent decoding of B frame.The memory is required to certainly store motion picture datacorresponding to two frames therein. The re-arrangement or sorting ofthe data in frame order is performed using each memory corresponding tothe two frames. Since the data is coded in one frame unit, the framedata cannot be displayed simultaneously with decoding even in the caseof the B frame when one frame is made up of two interlaced fields as inthe case of a television signal. It is necessary to convert the framedata to field data sorted in the order of scanning lines. Even for thispurpose, a memory corresponding to about one frame is required.

Further, image or picture signals compressed by the MPEG-2 system areclassified into several categories. Special emphasis is placed on thetwo categories called a “main level (ML)” and a “high level (HL)” inparticular from an application standpoint.

The main level corresponds to the NTSC system of horizontal 720pixels×vertical 480 scanning lines×frame frequency of 30 Hz and isadopted for a satellite digital broadcast. The high level corresponds toa high-definition image or picture expressed in horizontal 1920pixels×vertical 1080 scanning lines×frame frequency of 30 Hz. It hasbeen determined to be adopted for a US ground wave digital broadcastintended to provide high picture-quality broadcasting services. The USground wave digital broadcast has been introduced in the May 1997 issue,pp 47-53 of Nikkei Microdevice, for example.

The capacity of a memory required to decode the coded motion picturedata based on the MPEG-2 system is equivalent to one added with that fora coded image or pictorial data buffer for temporarily storing a codedimage upon decoding in addition to the capacity corresponding to thethree frames. The capacity of the coded image data buffer (VBV)corresponds to 1,835,008 bits in main level and 9,781,248 bits in highlevel. Even in the case of combinations of coding devices and decoderdevices different in manufacturer, this capacitive value is determinedby the MPEG-2 system as the required minimum capacity necessary toalways maintain the assurance of suitable coding/decoding.

As also introduced in the May 1997 issue, pp 47-53 of NikkeiMicrodevice, the picture formats of the coded motion picture data rangeover many divergences. Thus, the display of decoded motion picture datacorresponding to these all picture formats on a specific monitor needsto use a display device capable of displaying all these picture formatsor utilize a format converting device between a decoder device and adisplay. The latter is advantageous to reduce the cost of the monitor.

Further, the satellite digital broadcast and the ground wave digitalbroadcast are not independent services for users who receive thesebroadcasts and enjoy the same. It is very natural that there is a demandthat the users desire to enjoy even the conventional analog broadcastthrough the same television receiver. It is necessary to meet thisdemand.

SUMMARY OF THE INVENTION

An example of a device for decoding coded motion picture data, which canbe used in a receiver for broadcast service in which picture formats ofcoded motion picture data have a variety of picture sizes as in the USground wave digital broadcast, has been disclosed in Japanese PatentApplication Laid-Open No. Hei 8-205161. This example is a proposalwherein a high-definition motion picture (HD:High Definition) is decodedwhile being downsampled to a standard motion picture (SD: StandardDefinition) corresponding to the same format as the analog broadcast,thereby facilitating provisions to a plurality of picture formats.

However, the present example has a problem in that the high-definitionpicture data is merely outputted as the standard picture data and hencethe users cannot enjoy a precious high picture-quality broadcast.Further, the example also contains no mentions of a configurationcapable of receiving the analog broadcast simultaneously.

An object of the present invention is to solve the above problems,facilitate provisions to broadcasted variety of picture formats andrealize simultaneous reception of an analog broadcast.

According to one aspect of the invention, for achieving the aboveobject, the present invention comprises means for decoding motionpicture data used in a digital broadcast, memory means for storing thedecoded motion picture data therein, first on-screen data multiplexingmeans for mixing the decoded motion picture data with first on-screendata, first picture format converting means for converting the firston-screen data-mixed motion picture data into format form, and secondon-screen data multiplexing means for mixing the format-converted motionpicture data with second graphics data, whereby the second on-screendata-mixed motion picture data is outputted. Thus, the motion picturedata used in the digital broadcast can be outputted in an arbitrarypicture format so that a high picture-quality display can be done. Theon-screen data allows the high picture-quality display too. Further, thepresent invention includes second picture format converting means. Theoutput of second format-converted motion picture data as an output for arecording device from the second picture format converting means makesit possible to use the conventional analog broadcasting recordingdevice.

Further, the present invention includes picture data capturing means forinputting motion picture data used in an analog broadcast therein, andmotion picture data memory storing means for allowing the memory meansto store the motion picture data used in the analog broadcast. Byapplying the first picture format converting means even to the motionpicture data used in the analog broadcast, the motion picture data canbe outputted or displayed without drawing a distinction between theanalog broadcast and the digital broadcast.

According to the present invention, as has been described above,high-definition motion picture data can be displayed while remaininghigh in image quality as the high-definition motion picture data.Further, even if the data is broadcasted in the form of a plurality ofimage or picture formats, their display picture formats are converted tothe same. It is therefore possible to achieve a reduction in the cost ofa monitoring device. Since standard motion picture data can be outputtedsimultaneously with the display motion picture data in addition to thedisplay motion picture data, the conventional analog broadcastingrecording device can be also utilized. Further, since the conventionalanalog broadcast can be also converted to a high-definition motionpicture format and displayed in this form, even the conventional analogbroadcast can be displayed with high picture quality, describedspecifically, an easy-to-see screen from which scanning lineinterference like line flicker (corresponding to such a phenomenon thatfine points are flickering) can be provided. Moreover, since data can bedisplayed in picture-in-picture form or graphics data can be on-screendisplayed, a table for an electronic program guide can be displayed.According to the electronic program guide, a cursor of a remotecontroller is set to or aligned with a program to thereby make itpossible to choose a channel and make a recording reservation. Theprovision of two-system OSDs allows graphics to be displayed on TV butunrecorded on VTR as well as superimposition of graphics on both the TVdisplay and VTR recording, thus making it possible to implement aneasy-to-understand user interface.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, objects and advantages of the presentinvention will become more apparent from the following description whentaken in conjunction with the accompanying drawings wherein:

FIG. 1 shows a first embodiment of the present invention and is a blockdiagram illustrating the present invention applied to a digitalbroadcasting receiver;

FIG. 2 is a block diagram depicting a reformatter for converting animage format into reformatted form;

FIG. 3 is a diagram for describing operation modes of the reformatteremployed in the first embodiment;

FIG. 4 shows a second embodiment of the present invention and is a blockdiagram showing the present invention applied to a digital broadcastingreceiver;

FIG. 5 is a diagram for explaining operation modes of a reformatteremployed in the second embodiment;

FIG. 6 shows a third embodiment of the present invention and is a blockdiagram illustrating the present invention applied to a digitalbroadcasting receiver;

FIG. 7 shows a fourth embodiment of the present invention and is a blockdiagram illustrating the present invention applied to a digitalbroadcasting receiver;

FIG. 8 is a block diagram illustrating an NTSC decoder and an inputprocessor;

FIG. 9 depicts a fifth embodiment of the present invention and is ablock diagram illustrating the present invention applied to a digitalbroadcasting receiver;

FIG. 10 illustrates a sixth embodiment of the present invention and is ablock diagram showing the present invention applied to a digitalbroadcasting receiver;

FIG. 11 shows a seventh embodiment of the present invention and is ablock diagram illustrating the present invention applied to a digitalbroadcasting receiver;

FIG. 12 illustrates a modification of the first embodiment of thepresent invention and is a block diagram illustrating the presentinvention applied to a digital broadcasting receiver;

FIG. 13 depicts another modification of the first embodiment of thepresent invention and is a block diagram illustrating the presentinvention applied to a digital broadcasting receiver;

FIG. 14 shows a modification of the fourth embodiment of the presentinvention and is a block diagram illustrating the present inventionapplied to a digital broadcasting receiver;

FIG. 15 illustrates another modification of the fourth embodiment of thepresent invention and is a block diagram illustrating the presentinvention applied to a digital broadcasting receiver;

FIG. 16 depicts a modification of the fifth embodiment of the presentinvention and is a block diagram illustrating the present inventionapplied to a digital broadcasting receiver; and

FIG. 17 shows another modification of the fifth embodiment of thepresent invention and is a block diagram illustrating the presentinvention applied to a digital broadcasting receiver.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will hereinafter bedescribed with reference to the accompanying drawings.

FIG. 1 shows a first embodiment of the present invention and is a blockdiagram illustrating the present invention applied to a digitalbroadcasting receiver. In FIG. 1, reference numerals 1, 2, 3, 4, 5, 6,7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 and 23indicate a digital broadcasting antenna, a digital broadcasting tuner, afront/end circuit, a descrambler, a transport demultiplexer, a clockgenerator, a system controller, a memory, a memory interface, a memorybus, a video header parser, a video decoder, a first on-screen displaycircuit (hereinafter described as “OSD circuit”), a reformatter, asecond OSD circuit, a first digital-analog converter (hereinafterdescribed as “DAC”), a monitor driving circuit, a monitor, an audioheader parser, an audio decoder, a second DAC, a speaker drivingcircuit, and a speaker, respectively.

A broadcasting wave is received by the digital broadcasting antenna 1and thereafter converted into frequency form by the digital broadcastingtuner 2. The front/end circuit 3 demodulates a 8-PSK-modulated receivedsignal, for example and corrects its transmission error using errorcorrection parity so as to output a transport stream. With respect tothe transport stream, principal digital data thereof is scrambled in apay broadcast. The scrambled data is descrambled by the descrambler 4with key information outputted from the system controller 7 as anauxiliary input (where detailed connections around the system controller7 are omitted because the drawing is put out of order). Further, severalprograms having different contents are generally contained in thetransport stream in multiplexed form. The transport demultiplexer 5receives instructions for each desired user's program through the systemcontroller 7 to separate one program from the plurality of programs andfurther separate it into coded video data and coded audio dataconstituting coded motion image or picture data. The separatedrespective code data are temporarily stored in a dedicated area of thememory 8 through the memory bus 10 and the memory interface 9. Further,the transport demultiplexer 5 simultaneously separates the multiplexedkey information, program multiplex table information representing how tomultiplex the respective programs, etc. other than the motion picturedata from the input formation or stream and transmits the separatedinformation to the system controller 7. Their transmission is performedbefore the separation and selection of one program.

Moreover, the transport multiplexer 5 extracts time information from thetransport stream and sends it to the clock generator 6. The clockgenerator 6 controls an internal timer so that the time of a decoderdevice is set identical to that on the transmitting side, and generatesa clock signal used within the decoder device in synchronism withinformation from the corresponding timer. In the drawing, lines fordistributing the clock signal are omitted to avoid the cumbersomeness oftheir description.

The coded video data stored in the memory 8 is read from the memory 8.The video header parser 11 obtains format information such as an imageor pictorial size or the like as header information from the read dataand transmits the format information to the video decoder 12 and thesystem controller 7. Further, the video header parser 11 extracts titledata about a closed caption or the like, for example, related to thecontents of the coded video data and sends it to the system controller7. While the video decoder 12 decodes the coded video data in accordancewith the extracted image or picture format information, it writes thedecoded image or pictorial data into a predetermined frame memory areaof the memory 8 through the memory bus 10 and the memory interface 9 inits decoding process. As described above, the frame memory areacorresponds to three frames, and I and P pictures are read as image orpictorial data in a reference frame upon decoding P and B pictures.These decoding operations normally produce pictorial data in a framecomprised of a combination of two fields, whereas the video decoder 12reads and outputs the pictorial data from the frame memory area of thememory in order of scanning lines every field per display framerearranged or sorted in order of the display frames.

The first OSD circuit 13 mixes on-screen data into the output pictorialdata of the video decoder 12. The mixed on-screen data corresponds todata processed for display from the above-described title data about theclosed caption by the system controller 7. The data processed fordisplay is stored in the memory 8 before it is sent to the first OSDcircuit 13 in advance. Each time the first OSD circuit 13 requires datain accordance with the output pictorial data, the processed data issupplied via the memory interface 9 and the memory bus 10 to the firstOSD circuit 13 where the output pictorial data and the on-screen dataare mixed together in synchronism with each other. Further, the mixedpictorial data is supplied to the reformatter 14.

FIG. 2 is a block diagram of the reformatter 14 for converting an imageor picture format into reformatted form. In FIG. 2, reference numerals141, 142, 143 and 144 indicate selectors which select and output any ofthree inputs A, B and C, respectively. Reference numeral 145 indicates amemory controller, reference numeral 146 indicates a horizontal sizeconverter, and reference numeral 147 indicates a vertical sizeconverter, respectively. The selectors designated at reference numerals141 through 144 control the selection of any input of A, B and C by thesystem controller 7 according to the ratio between an image size of thecoded video data and an image size displayed on the monitor 18 to bedescribed later.

FIG. 3 is a diagram for describing operation modes of the reformatter14. Horizontal 1920 pixels (effective component), vertical 1080 lines(effective component), a frame frequency 30 Hz, 2:1 interlace scanning,and a screen aspect ratio 16:9, which are well known as ahigh-definition image (HDTV), are assumed to be a scanning format ofimage data displayed on the monitor 18. FIG. 3 shows size conversioncoefficients of the horizontal size converter 146 and the vertical sizeconverter 147, and which input is selected by each of the fourselectors, for a plurality of scanning formats. When, for example, animage size inputted to the reformatter 14, corresponding to the outputof the first OSD circuit 13, has a progressive scanning format ofhorizontal 1280 pixels×vertical 720 scanning lines as shown in the thirdscanning format from the top in FIG. 3, a screen aspect ratio of 16:9,and a frame frequency of 60 Hz, the number of pixels is converted from1280 pixels to 1920 pixels with a horizontal size conversion ratio of(3/2) times, and the number of scanning lines is converted from 720scanning lines to 1080/2 scanning lines with a vertical size conversionratio of (3/4) times. In order to convert progressive scanning tointerlace scanning, frames of 60 Hz are respectively caused tocorrespond to fields, and the phases of scanning lines in two fields aremade different from each other.

The reformatter 14 has a memory controller 145 and utilizes the memory 8through the memory bus 10 or the like to output the format-convertedpictorial data at a predetermined data rate. The selectors 141 through144 are provided so as to minimize the usage capacity of the memory 8and a data band width of the memory bus 10. That is, when the conversionratios of the horizontal size converter 146 and the vertical sizeconverter 147 are smaller than 1, the selectors 141 through 144 arecontrolled so that the horizontal size converter 146 and the verticalsize converter 147 are placed before the memory controller 145, whereaswhen they are greater than 1, the selectors 141 through 144 arecontrolled so that they are placed after the memory controller 145.

Since the vertical size conversion coefficient is smaller than 1 in theabove-described embodiment, the selector 143 selects A and inputs inputpictorial data to the vertical size converter 147. The selector 141selects C so that the output of the vertical size converter 147 is setas an input to the memory controller 145, after which it is written intothe memory 8. Thereafter, the pictorial data is read along apredetermined rate from the memory 8. While the pictorial data read fromthe memory 8 is outputted from the memory controller 145, it is set asan input to the horizontal size converter 146 by allowing the selector142 to select B. The reason why the horizontal size converter 146 isplaced after the memory controller, is that the size conversion ratio islarger than 1. If both the size conversion ratios are greater than 1,then the vertical size converter 147 and the horizontal size converter146 are both placed after the memory controller 145. However, thevertical size converter 147 is placed in front of the horizontal sizeconverter 146. This is because this placement is effective in reducingthe size of a line buffer (not shown) provided in the vertical sizeconverter 147. When both the size conversion ratios are smaller than 1and both the vertical size converter 147 and the horizontal sizeconverter 146 are placed before the memory controller 145 due to thesimilar reason, the horizontal size converter 146 is provided so as toprecede the vertical size converter 147. Returning to the illustratedcase, the selector 144 finally selects the output (B) of the horizontalsize converter 146 and sets it as the output of the reformatter 14.

Referring back to FIG. 1, a further description will be madecontinuously. The output of the reformatter 14 is inputted to the secondOSD circuit 15. The second OSD circuit 15 mixes graphics data such as aprogram guide or the like into the input pictorial data. The output ofthe second OSD circuit 15, which has been mixed with the graphics data,is converted to an analog signal by the first DAC 16, followed bydisplay on the screen of the monitor 18 through the monitor drivingcircuit 17.

The graphics data mixed by the second OSD circuit 15 is produced by thesystem controller 7 and is stored in the memory 8 in advance, from whichthe second OSD circuit 15 reads it based on instructions given from thesystem controller 7. With respect to the contents of a program guide,for example, the demultiplexer 5 font-converts character codes intographics data along the program multiplex table information separatedfrom the transport stream, after which it is produced by being mixedwith background graphics. The graphics data mixed by the second OSDcircuit 15 is based upon the image or picture format of the output ofthe reformatter 14 but is not based on the picture format of the codedvideo data decoded by the video decoder 12. Therefore, the graphics datasuch as the characters or the like is thereafter displayed on themonitor 18 without being subjected to significant processing. Thegraphics data excellent in image or picture quality can be displayedthereon. The program guide is used when a user selects a program. Theability to display the character graphics data high in picture qualityleads to high quality of a user interface.

The coded audio data is read from the memory 8 by the audio headerparser 19. The audio header parser 19 specifies a coding system anddetects synchronous information from the coded audio data to therebyextract audio parameters such as a sampling frequency, etc. and notifiesthe same to the audio decoder 20. The audio decoder 20 decodes the codedaudio data using these audio parameters to thereby obtain audio data.The decoded audio data is converted to an analog audio signal by thesecond DAC 21, after which the analog audio signal is outputted from thespeaker 23 through the speaker driving circuit 22.

According to the embodiment as described above, the suitable setting ofthe operation of the reformatter 14 based on the picture format of thecoded video data allows the conversion of a plurality of image orpicture formats to one picture format and display thereof on the monitor18. This can simplify a scan deflection circuit (not shown) of themonitor 18 and is useful for a reduction in the cost of the entirereceiver. When the decoder device (corresponding to the antenna 1 to thefirst and second DACs 16 and 21) for the coded motion picture data, andthe monitor driving circuit 17, the monitor 18, and the speaker drivingcircuit 22 and the speaker 23 are provided as separate devices, theconventional analog broadcasting receiver can be also used as a monitordevice by setting the output of the decoder device for the coded motionpicture data to the same picture format as that for the present-existinganalog broadcast.

In the present embodiment as well, the two OSD circuits (13 and 15) areprovided. Thus, program inherent information suitable for displaying thebroadcasted coded video data in the form of the picture format andon-screen display information for improving the user interface can bemultiplexed into separately-decoded image data. This is also useful indisplaying the data on the monitor 18 in one picture format.

A second embodiment of the present invention will next be described withreference to FIG. 4. However, components shown in FIG. 4 identified bythe same reference numerals as those in FIG. 1 have already beendescribed and only the difference between FIG. 4 and FIG. 1 willtherefore be explained.

In FIG. 4, a second reformatter 24, a third DAC 25, a recording outputcircuit 26 and a recording device 27 are added to the first embodimentshown in FIG. 1.

The output pictorial data of the first OSD circuit 13 is supplied evento the second reformatter 24 as well as to the reformatter 14(hereinafter described as a first reformatter). The second reformatter24 is also identical to the first reformatter described using FIG. 2 inconfiguration. The second reformatter converts a picture format of theoutput thereof to the same SDTV as an analog broadcast regardless of thepicture format of the coded video data and outputs it to a recordingmedium such as a video tape through the DAC. Alternatively, the secondreformatter converts the picture format of the output thereof to thesame HDTV as a digital broadcast regardless of the picture format of thecoded video data and outputs it to a recording medium such as a DVD, aD-VHS or the like without having to use the DAC. The present embodimenttakes a configuration in which a monitor 18 and the recording device 27are both provided in FIG. 4. However, the present embodiment may take aconfiguration of a built-in VTR in which the driving circuit 17 and themonitor 18 shown in FIG. 1 are replaced by the output circuit 26 and therecording device 27. Alternatively, the present embodiment may take aconfiguration of a built-in DVD in which the DAC 16, driving circuit 17and monitor 18 shown in FIG. 1 are replaced with the output circuit 26and the recording device 27. These drawings are shown in FIGS. 12 and 13respectively. While the reformatters are shown in separate blockdiagrams as illustrated in the respective drawings, the first and secondreformatters may be commonly used as one reformatter.

FIG. 5 is a diagram showing size conversion ratios used to obtain anSDTV output by the second reformatter 24 and settings of selectors 141through 144 with respect to various input image or picture formats.Further, the output of the second reformatter 24 is used to performrecording to the recording device 27 through the third DAC 25 and therecording output circuit 26. Incidentally, the recording device 27 maybe constructed as the same device as the decoder device and receiveraccording to the present invention. It is however needless to say thatit may be provided as a separate device.

The present embodiment is characterized in that the second reformatter24 is provided to obtain recording image data with a view towardrecording it on a recording medium such as a video tape, a DVD, a D-VHS.Particularly when the output picture format of the second reformatter 24is set to SDTV, an inexpensive VTR like the already widely-available VHSsystem can be used. On the other hand, when the output picture format isset to HDTV, the DVD and D-VHS considered to be widely available fromnow on can be used.

A third embodiment of the present invention will next be described withreference to FIG. 6. Even in the description of the present embodiment,the description of certain elements common to those shown in thealready-described embodiments will be omitted.

In FIG. 6, a down mixer 28 and a fourth DAC 29 are added to the secondembodiment shown in FIG. 4. The down mixer 28 is used to down-mix 2CH ormonophonic audio data with, for example, 3/2-mode multichannel audiodata decoded by an audio decoder 20. The audio header parser 19 extractsthe most suitable downmixed parameters from coded audio data andperforms downmixing in accordance with the same. The downmixed audiodata is transmitted to the recording output circuit 26 through thefourth DAC 29 and recorded by a recording device 27 together with avideo signal.

In the present embodiment, the downmixed parameters instructed on thebroadcasting station side can be reflected faithfully so that highsound-quality recording can be done.

As a modification of the, present embodiment, the downmixed audio signalcorresponding to each of the outputs of the down mixer 28 and the fourthDAC 29 may be constructed so as to be supplied to the speaker drivingcircuits 22 shown in FIGS. 1 and 6. Since, in this case, the second DAC21 is unnecessary and the speakers 23 can be also reduced in number ascompared with the number of speakers corresponding to respectivemultichannels, this leads to a reduction in the cost of the receiver.

A fourth embodiment of the present invention will next be described withreference to FIG. 7. In a manner similar to the description made up tonow, the description of the already-described elements will be omitted.

In FIG. 7, reference numerals 30, 31, 32, 33 and 40 indicate an analogbroadcasting antenna, an analog broadcasting tuner, an NTSC decoder, aninput processor and a selector, respectively. The analog broadcastingantenna 30 and the analog broadcasting tuner 31 are ones used to receivethe conventional analog broadcast. When a user selects the display of avideo signal corresponding to the received analog broadcast on a monitor18, a system controller 7 is informed of it through the proper userinterface (e.g., an unillustrated remote controller) and transfers it torequired blocks. In the present mode, the analog broadcast signalreceived by the analog broadcasting antenna 30 and frequency-convertedby the analog broadcasting tuner 31 is converted to component signals(separated into luminance and color-difference signals) by the NTSCdecoder 32. The component signals passes through a memory bus 10 and amemory interface 9 via the input processor 33, selector 40 andreformatter 14 so as to be stored in a memory 8. Incidentally, asdescribed in FIG. 4, a built-in VTR may be configured in which thedriving circuit 17 and the monitor 18 shown in FIG. 7 are replaced withthe output circuit 26 and the recording device 27. Alternatively, anbuilt-in DVD may be constructed in which the DAC 16, driving circuit 17and monitor 18 shown in FIG. 7 are replaced by the output circuit 26 andthe recording device 27. These drawings are illustrated in FIGS. 14 and15.

FIG. 8 is a block diagram showing the NTSC decoder 32 and the inputprocessor 33. In FIG. 8, reference numeral 321 indicates a comb filter,reference numeral 322 indicates a color decoder, reference numeral 323indicates a luminance signal delay circuit, reference numeral 324indicates a synchronizing separator circuit, reference numerals 331,332, 333 indicate first to third analog-digital converters (hereinafterdescribed as “ADC”), reference numeral 334 indicates a multiplexer,reference numeral 335 indicates an analog clock generator, referencenumeral 336 indicates an enable signal generator, and reference numeral337 indicates an address generator, respectively.

An analog video signal inputted from the analog broadcasting tuner 31corresponds to a composite signal obtained by combining the luminancesignal and the two color-difference signals together in multiplex formas is generally known. As the form of the composite signal, there areknown the NTSC system used in Japan and North America, the PAL systemused in Europe (except for France) and the SECAM system used in Franceand Russia. While the NTSC system has been described in the presentdrawing, the present invention is not limited to the NTSC system. It isneedless to say that the present invention can be applied to the PAL andSECAM systems. The NTSC signal inputted from the analog broadcastingtuner 31 is separated into luminance and color or chrominance signals bythe comb filter 321. In response to the chrominance signals, the colordecoder 322 produces two color-difference signals called “(R-Y) and(B-Y)”, for example. On the other hand, the luminance signal is causedto coincide in delay time with the two color-difference signals by theluminance signal delay circuit 323. Further, the synchronizing separatorcircuit 324 detects horizontal and vertical synchronizing signals of theNTSC signal. These color-difference signals, luminance signal andhorizontal and vertical synchronizing signals are outputted to the inputprocessor 33.

The analog clock generator 335 of the input processor 33 performsmultiplication on the horizontal synchronizing signal to generate aclock signal of 13.5 MHz, for example. The clock signal is supplied tothe three ADC 331 through 333 so that the color-difference and luminancesignals inputted to these ADC 331 through 333 are converted into digitaldata. The color-difference and luminance signals converted to thedigital data are supplied to the multiplexer 334. The input processor 33is also supplied with a digital clock generated from the clock generator6 of the decoder device. The digital clock is higher in frequency thanthe clock signal generated by the analog clock generator 335. Thedigital clock has a frequency of 54 MHz or 81 MHz, for example but isone synchronized with the pictorial data in the coded bit stream of thetransport stream. Further, the digital clock is not synchronized withthe clock signal generated from the analog clock generator 335. Thedigital clock is inputted to the multiplexer 334, enable signalgenerator 336 and address generator 337.

The enable signal generator 336 receives the clock signal generated fromthe analog clock generator 335 and thereby generates an enable signalwith timing provided to allow the determination of digital dataoutputted from the three ADC 331 through 333 during one cycle of thedigital clock. Described specifically, since 81 MHz is equal to sixtimes 13.5 MHz but is in asynchronism in frequency, the leading edges ofclocks at five to seven times in the digital clock are included in onecycle of 13.5 MHz. The enable signal indicates a data determinationperiod of one cycle of 81 MHz during one cycle of 13.5 MHz. Themultiplexer 334 captures the color-difference and luminance signalsconverted to the digital data with the digital clock, using the enablesignal and performs asynchronous-synchronous clock conversion on thesame. Further, the enable signal is supplied even to the address signalgenerator 337 from which an address signal corresponding to the positionon the screen, of the digital data multiplexed by the multiplexer 334 isgenerated and outputted. As a result, the analog broadcast signalasynchronized with the transport stream transmitted in digitalbroadcasting can be processed with the digital clock. While the inputprocessor 33 shown in FIG. 8 performs multiplexing with the digitalclock, there is also known a method of multiplexing some or all of theluminance and color-difference signals in a state of an analog signal,converting it into digital form and thereafter performingasynchronous-synchronous clock conversion to timing of the digitalclock.

Returning to the description of FIG. 7, the memory 8 selects storingpictorial data according to the selection as to whether an image to bedisplayed on the monitor 18 is based on the digital broadcast or analogbroadcast. When it is based on the digital broadcast, it indicatespictorial data decoded by a video decoder 12. When it is based on theanalog broadcast, it corresponds to pictorial data digitally-convertedby the input processor 33. These are switched by the selector 40, afterwhich it is inputted to the reformatter 14 where it is converted to animage or picture format suitable for the monitor 18. The resultant datais displayed or projected onto the monitor 18 through a second OSDcircuit 15 and further the first DAC 16 and monitor driving circuit 17.When the pictorial data based on the analog broadcast is displayed, thereading of the pictorial data from the memory 8 by the reformatter 14 isperformed according to the digital clock and carried out based on thehorizontal and vertical synchronizing signals produced with the digitalclock. However, a series of operations for capturing motion picture databy the input processor 33 and writing the data into and reading the datafrom the memory 8 by the reformatter 14 implement a function as a framesynchronizer.

With respect to audio signals, an audio signal used in the digitalbroadcast, which is obtained by decoding the input by the audio decoder20, and an audio signal used in the analog broadcast, which is obtainedfrom the analog broadcasting tuner 31, are both supplied to a speakerdriving circuit 22 where either of them is selected according to thechoice of the pictorial data and the selected one sounds through aspeaker 23.

In the present embodiment described above, a receiver corresponding tothe analog broadcast and the digital broadcast can be implementedbecause the digital broadcast and the analog broadcast can be projectedonto the same monitor 18.

A fifth embodiment of the present invention will next be described withreference to FIG. 9. The description of certain common elements will beomitted in a manner similar to the description of the embodiments shownabove up to now.

In FIG. 9, reference numeral 34 indicates a third reformatter andreference numeral 35 indicates a PinP mixer, respectively.

While an input processor 33 converts a video signal used in an analogbroadcast into digital form as described above, the output thereof issupplied to the third reformatter 34. The third reformatter 34 is alsoidentical in configuration to that described in FIG. 2. The thirdreformatter 34 converts the video signal used in the analog broadcast toan arbitrary picture format while using a memory 8, and outputs theconverted output to the PinP mixer 35. The present embodiment isdifferent from the fourth embodiment. The pictorial data obtained byconverting the video signal used in the analog broadcast into digitalform, and the pictorial data obtained by decoding the coded video streamused in the digital broadcast by the video decoder 12 are both stored inthe memory 8. A first reformatter 14 converts the pictorial data used inthe digital broadcast into an arbitrary picture format using the memory8. Further, the third reformatter 34 has the frame synchronize functionof converting the pictorial data used in the analog broadcast tohorizontal and vertical synchronizing signals identical to the pictorialdata used in the digital broadcast. These two pictorial data arecombined into one by the PinP mixer 35. The combined pictorial data isprojected onto a monitor 18 through a first DAC 16 and a monitor drivingcircuit 17.

In the present embodiment as described above, the received images orpictures used in both the analog and digital broadcasts can be displayedsimultaneously using a picture-in-picture display format. Describedspecifically, a window is provided at an arbitrary position of afull-sized digital broadcast received image, and the analog broadcastreceived image reduced in size is put in the window. In contrast tothis, the digital broadcast received image and the analog broadcastreceived image are reversed, and two windows substantially identical insize are provided within a TV screen, whereby the digital broadcastreceived image and the analog broadcast received image can be projectedonto their windows.

As described in FIG. 4, a built-in VTR may be constructed in which thedriving circuit 17 and monitor 18 shown in FIG. 9 are replaced with anoutput circuit 26 and a recording device 27. Alternatively, a built-inDVD may be constructed in which the DAC 16, driving circuit 17 andmonitor 18 shown in FIG. 9 are replaced with an output circuit 26 and arecording device 27. These drawings are shown in FIGS. 16 and 17.

FIG. 10 shows a sixth embodiment of the present invention. In thepresent embodiment, only the blocks employed in the embodimentsdescribed until now are utilized and no new ones are provided. If thepresent embodiment is compared with the fifth embodiment shown in FIG.9, then the second reformatter 24, third DAC 25, recording outputcircuit 26, recording device 27, downmixer 28 and fourth DAC 29described in the third embodiment of FIG. 6 are added thereto. Theseblocks are provided for recording of decoded motion picture dataavailable in the digital broadcast. The second reformatter 24 readsdecoded pictorial data used in the digital broadcast from a memory 8independently of a first reformatter 14 and a third reformatter 34 andconverts it to an image or picture format of SDTV for recording. As aresult, in the present embodiment, the decoded motion picture data usedin the digital broadcast can be recorded in the recording device 27regardless of whether pictorial data displayed on the monitor 18 isbased on the analog broadcast or the digital broadcast, or both arebased on a picture-in-picture format.

A seventh embodiment of the present invention will next be describedwith reference to FIG. 11. If the present embodiment is compared withthe sixth embodiment shown in FIG. 10, a second analog broadcastingantenna 36, a second analog broadcasting tuner 37, a second NTSC decoder38 and a second PinP mixer 39 are added to the present embodiment.

In the present embodiment, the aforementioned analog broadcastingantenna 30, analog broadcasting tuner 31 and NTSC decoder 32 performfirst analog broadcasting reception, and the second analog broadcastingantenna 36, second analog broadcasting tuner 37 and second NTSC decoder38 perform second analog broadcasting reception simultaneously. Thesecond PinP mixer has memory means thereinside and synchronizes the tworeceived analog broadcasting pictorial data with each other to therebyobtain one synthesized analog broadcasting pictorial data in thepicture-in-picture format. The input processor 33 inputs the combinedanalog broadcasting pictorial data therein and performs the sameoperation as that in the sixth embodiment subsequently to this input.

Thus, in the present embodiment, the picture-in-picture between theanalog broadcasts can be also carried out as well as the combination ofthe analog broadcast and the digital broadcast. If a tuner and a decoderused for the digital broadcast are prepared as another set and they arereplaced by the second analog broadcasting antenna 36, the second analogbroadcasting tuner 37 and the second NTSC decoder 38, then thepicture-in-picture between the digital broadcasts is also allowed. Evenin these cases, the same display as the description of thepicture-in-picture in FIG. 9 can be done.

While we have shown and described several embodiments in accordance withour invention, it should be understood that disclosed embodiments aresusceptible of changes and modifications without departing from thescope of the invention. Therefor, we do not intended to be bound by thedetails shown and described herein but indented to cover all suchchanges and modifications as fall within the ambit of the appendedclaims.

What is claimed is:
 1. A decoder device comprising: a motion picturedata decoder which decodes digital motion picture data to thereby obtaindecoded motion picture data; a memory which stores the decoded motionpicture data; a first picture format converter which converts thedecoded motion picture data into a picture format to obtain firstformat-converted motion picture data; a second picture format converterwhich converts the decoded motion picture data into a picture format toobtain second format-converted motion picture data; an output devicewhich outputs both the first format-converted motion picture data andthe second format-converted motion picture data; a voice data decoderwhich decodes multi-channel audio data included in the digital motionpicture data to obtain decoded multi-channel audio data; a downmixerwhich downmixes the decoded multi-channel audio data so as to reduce anumber of channels to obtain downmixed audio data; and an output devicewhich outputs the decoded multi-channel audio data and the downmixedaudio data.
 2. A decoder device, comprising: a motion picture datadecoder which decodes digital motion picture data to thereby obtaindecoded motion picture data; a memory which stores the decoded motionpicture data therein; a first on-screen data multiplexer which mixes thedecoded motion picture data with first graphics data to thereby obtainfirst on-screen data-mixed motion picture data; a first picture formatconverter which converts the first on-screen data-mixed motion picturedata into a picture format to thereby obtain first format-convertedmotion picture data; a second on-screen data multiplexer which mixes themotion picture data format-converted by the first picture formatconverter with second graphics data to thereby obtain second on-screendata-mixed motion picture data; a second picture format converter whichconverts the first on-screen data-mixed motion picture data into apicture format to thereby obtain second format-converted motion picturedata; an output device which outputs the second on-sceen data-mixedmotion picture data therefrom; and an output device which outputs thesecond format-converted motion picture data therefrom.
 3. A decoderdevice, comprising: a motion picture data decoder which decodes digitalmotion picture data to thereby obtain decoded motion picture data asfirst motion picture data; a memory which stores the decoded motionpicture data therein; a picture data capturing device which inputssecond motion picture data therein; a motion picture data storing devicewhich enables the memory to store the second motion picture datatherein; a first on-screen data multiplexer which mixes the first motionpicture data with first graphics data to thereby obtain first on-screendata-mixed motion picture data; a picture format converter whichconverts each of the first on-screen data-mixed motion picture data andthe second motion picture data into a picture format to thereby obtainformat-converted motion picture data; a second on-screen datamultiplexer which mixes the format-converted motion picture data withsecond graphics data to thereby obtain second on-screen data-mixedmotion picture data; and an output device which outputs the secondon-screen data-mixed motion picture data therefrom.
 4. A receiver,comprising: a motion picture data decoder which decodes digital motionpicture data to thereby obtain decoded motion picture data as firstmotion picture data; a memory which stores the decoded motion picturedata therein; a picture data capturing device which inputs second motionpicture data therein; a motion picture data storing device which enablesthe memory to store the second motion picture data therein; a firston-screen data multiplexer which mixes the first motion picture datawith first graphics data to thereby obtain first on-screen data-mixedmotion picture data; a picture format converter which converts each ofthe first on-screen data-mixed motion picture data and the second motionpicture data into a picture format to thereby obtain format-convertedmotion picture data; a second on-screen data multiplexer which mixes theformat-converted motion picture data with second graphics data tothereby obtain second on-screen data-mixed motion picture data; and adisplay which displays the second on-screen data-mixed motion picturedata thereon.
 5. A decoder device, comprising: a motion picture datadecoder which decodes digital motion picture data to thereby obtaindecoded motion picture data as first motion picture data; a memory whichstores the decoded motion picture data therein; a picture data capturingdevice which inputs second motion picture data therein; a motion picturedata storing device which enables the memory to store the second motionpicture data therein; a first picture format converter which convertsthe first motion picture data into a picture format to thereby obtainfirst format-converted motion picture data; a second picture formatconverter which converts the second motion picture data into a pictureformat to thereby obtain second format-converted motion picture data; apicture-in-picture mixer which mixes the first format-converted motionpicture data and the second format-converted motion picture datatogether to thereby obtain picture-in-picture motion picture data; andan output device which outputs the picture-in-picture motion picturedata.
 6. A receiver, comprising: a motion picture data decoder whichdecodes digital motion picture data to thereby obtain decoded motionpicture data as first motion picture data; a memory which stores thedecoded motion picture data therein; a picture data capturing devicewhich inputs second motion picture data therein; a motion picture datastoring device which enables the memory to store the second motionpicture data therein; a first picture format converter which convertsthe first motion picture data into a picture format to thereby obtainfirst format-converted motion picture data; a second picture formatconverter which converts the second motion picture data into a pictureformat to thereby obtain second format-converted motion picture data; apicture-in-picture mixer which mixes the first format-converted motionpicture data and the second format-converted motion picture datatogether to thereby obtain picture-in-picture motion picture data; and adisplay which displays the picture-in-picture motion picture data.
 7. Adecoder device, comprising: a motion picture data decoder which decodesdigital motion picture data to thereby obtain decoded motion picturedata as first motion picture data; a memory which stores the decodedmotion picture data therein; a picture data capturing device whichinputs second motion picture data therein; a motion picture data storingdevice which enables the memory to store the second motion picture datatherein; a first on-screen data multiplexer which mixes the first motionpicture data with first graphics data to thereby obtain first on-screendata-mixed motion picture data; a first picture format converter whichconverts the first on-screen data-mixed motion picture data into apicture format to thereby obtain first format-converted motion picturedata; a second picture format converter which converts the second motionpicture data into a picture format to thereby obtain secondformat-converted motion picture data; a picture-in-picture mixer whichmixes the first format-converted motion picture data and the secondformat-converted motion picture data together to thereby obtainpicture-in-picture motion picture data; a second on-screen datamultiplexer which mixes the picture-in-picture motion picture data withsecond graphics data to thereby obtain second on-screen data-mixedmotion picture data; and an output device which outputs the secondon-screen data-mixed motion picture data therefrom.
 8. A receiver,comprising: a motion picture data decoder which decodes digital motionpicture data to thereby obtain decoded motion picture data as firstmotion picture data; a memory which stores the decoded motion picturedata therein; a picture data capturing device which inputs second motionpicture data therein; a motion picture data storing device which enablesthe memory to store the second motion picture data therein; a firston-screen data multiplexer which mixes the first motion picture datawith first graphics data to thereby obtain first on-screen data-mixedmotion picture data; a first picture format converter which converts thefirst on-screen data-mixed motion picture data into a picture format tothereby obtain first format-converted motion picture data; a secondpicture format converter which converts the second motion picture datainto a picture format to thereby obtain second format-converted motionpicture data; a picture-in-picture mixer which mixes the firstformat-converted motion picture data and the second format-convertedmotion picture data together to thereby obtain picture-in-picture motionpicture data; a second on-screen data multiplexer which mixes thepicture-in-picture motion picture data with second graphics data tothereby obtain second on-screen data-mixed motion picture data; and adisplay which displays the second on-screen data-mixed motion picturedata thereon.
 9. A decoder device, comprising: a motion picture datadecoder which decodes digital motion picture data to thereby obtaindecoded motion picture data as first motion picture data; a memory whichstores the decoded motion picture data therein; a picture data capturingdevice which inputs second motion picture data therein; a motion picturedata storing device which enables the memory to store the second motionpicture data therein; a first picture format converter which convertsthe first motion picture data into a picture format to thereby obtainfirst format-converted motion picture data; a second picture formatconverter which converts the second motion picture data into a pictureformat to thereby obtain second format-converted motion picture data; apicture-in-picture mixer which mixes the first format-converted motionpicture data and the second format-converted motion picture datatogether to thereby obtain picture-in-picture motion picture data; athird picture format converter which converts the first motion picturedata into a picture format to thereby obtain third format-convertedmotion picture data; and an output device which outputs both thepicture-in-picture motion picture data and the third format-convertedmotion picture data therefrom.
 10. A decoder device according to claim9, further comprising a motion picture data synthesizer whichsynthesizes a plurality of motion picture data to thereby createsynthesized motion picture data, and inputs the synthesized motionpicture data to the picture data capturing device as the second motionpicture data.